Muffler



. Panarea sept. 1. 1931 UNITED STA-'res PATENT'- OFFICE LUcrEN L. mias, OE BUFFALO, NEW Yoax, AssIGNOE To BUFFALO raaurssmn s'rEEL COMPANY, OE BUFFALO, NEW Yom:

MUEELEB Application tiled July 5, 1929. Serial No. 376,011.

This invention relates to muiilers or silencers for reducing noise caused `by the discharge of iuids under pressure, 'such for example as muiilers and silencers for use inconnection with internal combustion engines.

The Objects of this invent-ion are to provide al muiiler of this kind of simple an inexpensive construction and' high efiicie both with respect to Operation and economy in manufacture; alsoto provide a muiiler of this kind employing a. tapered shell in connection with a cylindrical shell for the purpose of obtaining a high degree of silencing with a lsmall resistance to the iow of gases throughthe muilier; also to provide a mu'flier of this kind with a plurality of restrictions or restricting nozzles so arranged with reference to discharge openings in a shell as to produce a reverse iiow of the gases; also to improve the construction of muiiiers in other respects hereinafter specified.

In the accompanying drawings, Fig. 1 is a central sectional view of a muiiier embodying this invention;

Fig. 2 is a transverse elevation' thereof, on line 2 2, Fig.` 1. f'

a In the particular embodiment of thevinvention shown in the accompanying drawings, A represents the outer shell of the muffier, which is substantially cylindrical in form, and B represents an inner shell whlch is of tapering or frustO-conical form', having vits larger endy arranged at the receiving end of the muiiier. The two shells are connected at pr near their Opposite ends by heads C and D, the head C being formed in the usual manner with cylindrical faces 5 and 6, to whichthe shells may be welded or otherwise secured, and this head is also provided with a tubular portion 7 which may be connected. with the exhaust pipe of an internal combustion engine. The other head D is provided with corresponding shoulders 8 and 9 and a tubular extension 10 through which the exhaust gases are discharged from the mufer. The heads C and D in the construction shown form the ends of the mufilers. but it will be understood that if it is desired to add additional muiing chambers at either end ofthe mulers, this can be done, in which case the heads C and D will become intermediate heads of a muiiler. In other words,`the mufiler described may be complete in itself or mayv form a part or unit of a-larger muiiier.

The inner shell B is provided with a baf.

leE which divides the inner shell into two muling chambers, the baiiie-E .in the construction shown being arranged nearer to the discharge end of the muliler so that there-l ceiving chamber within the inner shell is of greater length than. the discharge chamber. This baille may be made of a metal stamping having' an outer angc-12 which can be suitably secured to the inner shell B of the muiiler. A

The linner shell is provided with a series of apertures or openings through which gases `may pass, such openings or apertures 14,

and 16 b eing formed in the receiving chamber of the 1 inner4 shell and apertures 17 being formed in the discharge chamber.

The construction thus far described results iiow at substantially right angles to the di' rection of flow of gases in the'outer chamber of the muffler which disturbance in the How` results in further silencing. It will be also noted that by providing an inner tapering shell, the.` outer chamber of the mulii'er is of gradually increasing cross sectional area from the receiving end to the discharge end of the muiiier, Which enables this chamber to carry the increasingly larger quantity of gas caused by discharge of gas through the apertures 15 and 16, in addition to the gasesl discharged through apertures 1 4.

When the gases, reach the discharge end of the outer chamber of the muiiier, they flow radially toward the axis of the mnilier through the'opening 17. so that thiiwmimxs4 )ets or streams of these gases will impinge upon each other, with the result' of further reducing noises.

The receiving chamber of the inner shell of the muffler is also provided with one or more restrictions arranged at intervals therein, two restricting nozzles F and Gr being shown in the construct-ion illustrated. f These restricting or guide nozzles are preferably substantially funnel shaped,V and are arranged with their larger ends facing the incoming gases, so that the gases flow from the larger to the smaller. ends. The nozzles shown .areprovided with outer flanges 20 which are suitable secured to the inner face of the inner shell B of the muffler, and inwardly or rearwardly flaring or curved walls 21, which terminate in discharge openings 22. The restricting nozzles are arranged f just in -advance of the sets of apertures and 16, and consequently any gases flowing through these nozzles are projected at increased velocity" through 4the central portion of the receiving'chamber inthe shell B, and in order to permit suchgases, or any portions thereof, to How through the apertures 15 and 16, their direction of flow is re-` versed as indicated by the arrows. v This action has a decidedsilencing effect upon the gases. Each of these nozzles, in addition to guiding the flow of the gases, also act in the opposite manner as megaphones, thus tending to reduce noise.

In the operation of the muffler described, the gases entering the muller pass into the forward end of the inner shell B and some of the gases are immediately discharged into the outer'chamber of the `mufergthrough the openings 14 -in the shell B. Other portions of the entering gases pass through the restricting or guide nozzle F, which forces these gases to flow in the central or axial part of the receiving chamber in the shell B, and also reduces noise due to the reverse megaphone effect. A portion of these gases will then flow in the reverse direction and pass out through the aperture 15, mixing with the gases flowing in the outer chamber. Other parts of `the gases which have passed through the restricting nozzle F, pass through the second restricting nozzle G, and are then reversed in their direction of flow and pass out through the aperture v16 with asimilar effect upon the gases flowing in therouter chamber of the muffler; All of the gases from the outer chamber pass radially into the discharge chamber of the inner shell through the openings 17, causing thefvarious jets or streams of gases to impinge against cach other at the axis of the muffler, to produce further silencing, and the gases then pass through the discharge tube 10.

The muffler described has the advantage of, which disadvantage is tapering chamber B in such a manner that if,

by any chance these members become loosened, the force of the gases flowing in the muiiler. will tend to drive 'the nozzles and baille into the inner shell and thus wedge them in place, so that there will be no loosening or rattlingA of these parts, even ifl the Welded or other connection between these parts and the inner shell B becomes destroyed. The use of the taper in the shell not only helps the silencing of the noise, 'but also facilitates manufacture, since the welded joint between the discharge end vof the' shell B and the head D can be made more readily than would be the case if a cylindrical tube were used with a larger discharge end, due to the fact that the size of the discharge tube 10 is standard and cannot be increa-sed, and if the diameter at the discharge end of the shell B were greater, it would bel di'flicul't for a welding tool to reach through the tube 10 to the inner surface of the inner shell B at the shoulder 9 to make a satisfactory weld. Another advantage of the muffler described is tha-t by providing the discharge openings 14, 15 and 16 in the inner shell at intervals lengthwise thereof, the hot gases will be discharged into the outerchamber at different portions lengthwise thereof, so that radiation of heat from the outer shell of the muffler is substantially uniform at all parts of the outer shell. In cases where the gases are all discharged -into the outer chamber at one. end thereof, this end of the outer shell m0 becomes much hotter than other parts thereavoided by the construction described.

Claims:

A muliier having an outer cylindrical shell and an inner tapering she l' having its larger end arranged at the inlet end ofthe muliler, both of said shells eX- tending -throughout the length of the muffler,'a baille insaid inner shell dividing the uo same into a gas receiving chamber and a gas discharge chamber, a" series of frestricting nozzles 1n said receiving chamber, said ta er; ing shell forming with said outer shel an outer chamber which increases in cross sectional area toward the dischargel end of the mufller, discharge openings arranged at intervals in the portion of said inner shell surrounding saidv receiving chamber, some of said discharge openings being arranged im- ,20 mediately beyond said nozzles, and additional openings in the portion of said inner shell surrounding said discharge chamber'. for conducting gas i-rom said outer chamber to said discharge clfamber.

' iLUCIEN L. HAAS.

in that it is easy and inexpensive to construct and assemble. The baille E vand the restricting nozzles F and G are fitted into the fao substantiall mi- 

